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Abstract

To the editor: Nathan and colleagues (1) have described three patients who were resistant to the euglycemic effect of U-100 NPH insulin (both mixed species and pork) but who responded to U-500 regular insulin (pork). They claim that U-500 regular insulin may be effective when U-100 NPH and U-100 regular insulin are ineffective. I believe that the authors never gave U-100 regular insulin a chance. In any stable period, none of the patients received doses of U-100 regular insulin equal to those of the U-500 insulin. Therefore, the U-500 cannot be claimed to be a superior regular insulin in these